1. Field of the Invention
This invention relates to apparatus for cleaning radioactive tube banks which have open ends contained in a plane, preferably for cleaning the tube banks of tube bank condensers, comprising a high-pressure hose, which is adapted to be pushed through each of the tubes and which at its free end carries a spray nozzle for discharging a cleaning liquid.
2. Description of the Prior art
Water contaminated with radioactive material becomes available at a high rate, e.g., in nuclear power plants, and is decontaminated by evaporation. A large part of that water consists of rinsing water, which has been used to clean radioactive parts of the plant or clothes and which contains radioactive particles. As the water is evaporated, such radioactive particles are deposited on the tubes of the evaporator and of the condenser used to condense the water vapor so that said particles constitute insulating layers, which obstruct the heat transfer. In order to ensure that heat exchangers, evaporators, condensers and other equipment used to conduct radioactive water will be maintained in an operative condition, such equipment must be cleaned from time to time. In the present practice such cleaning is effected in that the tube banks, e.g., of a condenser, are opened and a high-pressure hose provided at its free end with a spray nozzle is pushed through each tube so that the water which in the high-pressure hose may be under a pressure of about 400 to 700 bars and which is sprayed from the spray nozzle will detach the deposits from the inside surfaces of the tube. That rinsing water consists of entirely desalted water. As the operator is exposed to the strong radioactive radiation leaving the open head of the condenser, an operator can perform such work only for a short time and must often be relieved.